Process Life Cycle in Operating System

April 22, 2025

Process Life Cycle in Operating System (OS)

Process Life Cycle in Operating System is one of the five states in which a process can be starting from the time it has been submitted for execution, till the time when it has been executed by the system. Here we will learn detailed explanation about each states.

Think of it like a human life –  you’re born, you grow, do tasks, take breaks, and eventually reach the end.

Stages of a Process in Life Cycle

A process can be in any of the following states –

  • New state
  • Ready state
  • Running state
  • Waiting state
  • Terminated
  • Imagine a unit process that executes a simple addition operation and prints it.
Process queue

New State

  • Process it submitted to the process queue, it in turns acknowledges submission.
  • Once submission is acknowledged, the process is given new status.

Ready State

  • It then goes to Ready State, at this moment the process is waiting to be assigned a processor by the OS
Ready state

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Priority Scheduling

CPU Scheduling

FCFS Scheduling

Preemptive Scheduling

Running State

  • Once the Processor is assigned, the process is being executed and turns in Running State.
Running state

Wait and Termination State

  • Now the process can follow the following transitions –
    • The process may have all resources it needs and may get directly executed and goes to Termination State.
    • Process may need to go to waiting state any of the following
      • Access to Input/Output device (Asking user the values that are required to be added) via console
      • Process maybe intentionally interrupted by OS, as a higher priority operation maybe required, to be completed first
      • A resource or memory access that maybe locked by another process, so current process goes to waiting state and waits for the resource to get free.
    • Once requirements are completed i.e. either it gets back the priority to executed or requested locked resources are available to use, the process will go to running state again where, it may directly go to termination state or may be required to wait again for a possible required input/resource/priority interrupt.
  • Termination
Wait and termination state
Process Cycle 1New State
Process Cycle 2Read State
Process Cycle 3Running State
Process Cycle 4Waiting State
Process Cycle 4Terminated State

Summary

  1. New – New Process Created
  2. Ready – Process Ready for Processor/computing power allocation
  3. Running – Process getting executing
  4. Wait – Process waiting for signal
  5. Terminated – Process execution completed

Apart from the above some new systems also propose 2 more states of process which are –

  1. Suspended Ready – There maybe no possibility to add a new process in the queue. In such cases its can be said to be suspended ready state.
  2. Suspended Block – If the waiting queue is full
Process Lifecyle in OS

Final Thoughts

Understanding the process life cycle helps us know how the operating system manages different tasks running on a computer. Every process goes through stages like new, ready, running, waiting, and terminated – just like steps in a journey.

These stages make sure that the system runs smoothly, handles multiple tasks at once, and gives each process a fair chance to use the CPU.

In simple words, the process life cycle is the reason your computer can open apps, play music, and run programs all at the same time without getting confused.

FAQs

Yes, if the CPU needs to switch to another process (like in multitasking), the current running process goes back to the ready state and waits for its next turn.

The process is paused and waiting for something to happen — like reading a file, getting user input, or waiting for data. It will go back to ready once it’s done waiting.

The main states are:

  • New (just created),
  • Ready (waiting to run),
  • Running (being executed),
  • Waiting (paused for input/output),
  • Terminated (finished or stopped).

It helps the operating system manage many tasks at once. By tracking each process’s stage, the system ensures everything runs smoothly without crashing or slowing down.